1. Field of the Invention.
The present invention relates to a hydraulic press construction wherein the press is rigid, and the actual pressing cylinders are integrated into clamps which are carried by a movable member that can be opened and closed for charging a mold, and for removing a finished part.
2. Description of the Prior Art.
Various hydraulic presses for forming materials have been advanced, including ones that have rigid cross heads that are clamped onto smooth columns, for example, a press as shown in U.S. Pat. No. 4,457,684, issued July 3, 1984. That specification shows a hydraulic press which has clamps on the cross head to clamp the cross head in place, and separate molding cylinders that are positioned below a lower platen, and which provides a wide range of movability during the press operation. The cross head construction shown in U.S. Pat. No. 4,457,684 also shows a rigid, relatively light weight cross head which distributes the stress substantially uniformly across the supported platen. the ram and bed of the present press accomplishes distribution of stress as well, but in a different manner.
Hydraulically operated sleeve clamps that clamp onto smooth columns, and have two interfitting parts that prevent slip between the two parts are shown in U.S. Pat. No. 4,509,910, issued Apr. 9, 1985.
U.S. Pat. No. 3,449,795 shows a type of a mold closer that has a clamp that is hydraulically operated to clamp to a smooth column, and which has a built-in pressure cylinder. This patent also shows a configuration for latching members into existing grooves in columns, which are hydraulically operated as well.
Further, U.S. Pat. No. 4,565,517 illustrates a hydraulic press that has clamps with integrated pressing cylinders, but arranged in a substantially different configuration from the present device and having a requirement for a heavy press frame.